Bug 76543

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Description of problem:
Resolver.  General problem with name to IP resolution.

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
See Additional information section for configuration information
	

Actual Results:  See Additional information section for configuration information

Expected Results:  names should be resolved to IP via files when files specified
first.  BIND should resolve locally first when local host names are used.

Additional info:

There appears to be a general issue with name to IP resolution in RedHat Linux
8.0.  This is present in a number of different situations.

Senerio 1.  Initially I was working with a simple files based network setup. 
That is my system names were listed in /etc/hosts both as fqd names (dot 3) and
short (just server name) name alias.  Both /etc/host.conf and /etc/nsswitch.conf
were set for files first and then dns.  My IP's nameservers where set in
/etc/resolv.conf.  The first thing I noticed is that when trying to connect to
systems on my local network with this setup ssh and telnet attempt to resolve
via DNS first.  Only after the attempt times out or otherwise fails will it fall
back to files.  This is true both with short and fqd system names.  Oddly enough
ping is not effected.  With ping the hostnames appeared to immediately resolve
directly from /etc/hosts without an internet DNS lookup attempt.  I am throughly
convinced the behavior under this senerio is a bug.

Senerio 2.  Decided to setup a DNS (BIND) server for my local network.  Slightly
different resolution pattern observed.   All fqd (dot 3) local network system
names resolved without issue for ssh, telent, and ping.  However, short names
did not appear to resolve properly.  Encountered delays before they would
resolve via local DNS (I had commented out entries in /etc/hosts and had
internet DNS disabled to ensure I was resolving only through my DNS).  At first
I thought this was a setup problem with my DNS server but I found that when I
tried ping the system names resolved immediately without delay even with just
short (host) names.  It seems almost as if the domain name is not being
appropriately taken into account when using ssh and telnet during the hostname
resolution.  I tried entering the domain into /etc/resolve.conf but there was no
change.  Either way ssh and telnet attempted to contact outside DNS servers
(this could be evidenced in firewall logs after setting the fw to drop outbound
DNS at the gateway) before using the local zone information, however, ping
immediately resolved using the local zone information without attempting to
contact internet servers.

Sernerio 3.  The final thing to report is that I have just observed that mail
(sent from anacron to root on the local system in this case) appears to be
subject to external DNS resolution attempts when using the files based network
setup described in senerio 1.